XCFHandler.php

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<?php
use MediaWiki\FileRepo\File\File;
use MediaWiki\Libs\UnpackFailedException;
use Wikimedia\StringUtils\StringUtils;
 
class XCFHandler extends BitmapHandler {
    public function mustRender( $file ) {
        return true;
    }
 
    public function getThumbType( $ext, $mime, $params = null ) {
        return [ 'png', 'image/png' ];
    }
 
    private static function getXCFMetaData( $filename ) {
        # Decode master structure
        $f = fopen( $filename, 'rb' );
        if ( !$f ) {
            return null;
        }
        # The image structure always starts at offset 0 in the XCF file.
        # So we just read it :-)
        $binaryHeader = fread( $f, 26 );
        fclose( $f );
 
        try {
            $header = StringUtils::unpack(
                "A9magic" . # A: space padded
                    "/a5version" . # a: zero padded
                    "/Nwidth" . # \
                    "/Nheight" . # N: unsigned long 32bit big endian
                    "/Nbase_type", # /
                $binaryHeader
            );
        } catch ( UnpackFailedException ) {
            return null;
        }
 
        # Check values
        if ( $header['magic'] !== 'gimp xcf' ) {
            wfDebug( __METHOD__ . " '$filename' has invalid magic signature." );
 
            return null;
        }
        # TODO: we might want to check for correct values of width and height
 
        wfDebug( __METHOD__ .
            ": canvas size of '$filename' is {$header['width']} x {$header['height']} px" );
 
        return $header;
    }
 
    public function getSizeAndMetadata( $state, $filename ) {
        $header = self::getXCFMetaData( $filename );
        $metadata = [];
        if ( $header ) {
            // Try to be consistent with the names used by PNG files.
            // Unclear from base media type if it has an alpha layer,
            // so just assume that it does since it "potentially" could.
            switch ( $header['base_type'] ) {
                case 0:
                    $metadata['colorType'] = 'truecolour-alpha';
                    break;
                case 1:
                    $metadata['colorType'] = 'greyscale-alpha';
                    break;
                case 2:
                    $metadata['colorType'] = 'index-coloured';
                    break;
                default:
                    $metadata['colorType'] = 'unknown';
            }
        } else {
            // Marker to prevent repeated attempted extraction
            $metadata['error'] = true;
        }
        return [
            'width' => $header['width'] ?? 0,
            'height' => $header['height'] ?? 0,
            'bits' => 8,
            'metadata' => $metadata
        ];
    }
 
    public function isFileMetadataValid( $file ) {
        if ( !$file->getMetadataArray() ) {
            // Old metadata when we just put an empty string in there
            return self::METADATA_BAD;
        }
 
        return self::METADATA_GOOD;
    }
 
    protected function hasGDSupport() {
        return false;
    }
 
    public function canRender( $file ) {
        $xcfMeta = $file->getMetadataArray();
        if ( isset( $xcfMeta['colorType'] ) && $xcfMeta['colorType'] === 'index-coloured' ) {
            return false;
        }
        return parent::canRender( $file );
    }
}